Tornheim, KeithCrickmore, MichaelMadamidola, Nicholas Isaac2023-02-152023-02-152022https://hdl.handle.net/2144/45615The positive or negative affect that an animal has to an external stimulus is known as valence. In order to survive, an organism’s brain must appropriately encode pleasurable and unpleasurable stimuli and ascribe a specific valence to them in order that the animal correctly learn appetitive and aversive behaviors. In this study, optogenetic tools were employed to conduct a genetic screen using Drosophila Melanogaster. Several lines of flies that displayed unusual phenotypes were identified, suggesting that when given the choice, these flies preferred to remain on an otherwise aversive stimulus (noxious heat) if it meant either stimulating or inhibiting certain neurons. We hypothesized that along with dopamine, and octopamine, the regulation of serotonin in may have a fundamental influence on both valence (the extent to which an organism is in a state of pleasure) and also copulation duration. Once these phenotypes were established, we then explored how altering the parameters of their environment would change their valence. The findings suggest that flies may indeed have a neurological correlate for feeling pleasure or displeasure.en-USNeurosciencesDrosophilaPleasureValenceThesis/Dissertation2023-02-09